Tuna

Overview

bScientific Name

Thunnus and Katsuwonus species

dWeight

40- 500 pounds

CLength

3-10 feet

eHabitats

Oceans

If fish were like cars, tuna would be the Ferraris of the ocean—sleek, powerful, and made for speed. Their torpedo-shaped bodies streamline their movement through water, and their special swimming muscles enable them to cruise the ocean highways with great efficiency.

Tuna are remarkable and impressive wild animals. The Atlantic bluefin can reach ten feet in length and weigh as much as 1500 pounds (more than a horse). Their specialized body shape, fins and scales enable some species of tuna to swim as fast as 43 miles per hour.

Tuna swim incredible distances as they migrate. Some tuna are born in the Gulf of Mexico, cross the entire Atlantic Ocean to feed off coast of Europe, and then swim all the way back to the Gulf to breed.

These extraordinary marine animals are also integral to the diet of millions and are one of the most commercially valuable fish. The majority of the market is made up of four species: skipjack, yellowfin, bigeye and albacore. As the methods of catching tuna have improved over the years, the conservation and management of tuna has not evolved as quickly. According to the United Nations Food and Agriculture Organization, most tuna stocks are fully exploited (meaning there is no room for fishery expansion) and some are already overexploited (there is a risk of stock collapse).

The Tuna Family

Why They Matter

Tuna are among the most commercially valuable fish on the planet. The Atlantic bluefin is a highly sought-after delicacy for sushi and sashimi in Asia—a single fish has sold for over $700,000! Driven by such high prices, fishermen use even more refined techniques to catch tuna. And the fish are disappearing as a result.

Although tuna do provide food and livelihoods for people, they are more than just seafood. Tuna are a top predator in the marine food chain, maintaining a balance in the ocean environment.

Threats

The tuna oceanic highways have turned into gauntlets lined with giant nets and endless lines of fishing boats. Fishermen have resorted to high-tech ways to catch tuna, including devices that draw the fish into bunches so that fishermen can catch more of them at once. Many of the world’s valuable tuna species face a number of urgent yet common threats to their continued existence such as significant population declines, poor international conservation management, and high levels of illegal, unreported, and unregulated (pirate) fishing.

Since juvenile yellowfin school with adult skipjack, they are increasingly caught as bycatch by vessels that target skipjack. The removal of these juveniles before they have a chance to spawn could lead to fewer yellowfin in the long term. Skipjack tuna are abundant throughout their range and populations appear healthy. However, since juvenile yellowfin and bigeye tuna often school with adult skipjack, they are caught by purse seine vessels that target skipjack.

According to information collected by the International Seafood Sustainability Foundation (ISSF), the Eastern Pacific stock of yellowfin is overfished and some overfishing is occurring in the Indian Ocean.The northern and southern Atlantic Ocean stocks of albacore are also overfished.The skipjack tuna, while quite resilient, could easily slip into a vulnerable state due to overfishing if improperly managed.

Bigeye tuna are prized in Asia for sashimi as well as frozen and fresh in other markets. As bluefin tuna populations shrink around the world, pressure on bigeye fisheries is increasing. According to information collected by the ISSF Scientific Advisory Committee, overfishing is occurring in Eastern and Western Pacific Oceans. Bluefin tuna populations have declined severely from overfishing and illegal fishing over the past few decades –not just Atlantic bluefin tuna, but also Pacific bluefin tuna and Southern bluefin tuna. Population declines have been largely driven by the demand for this fish in high end sushi markets.

Illegal fishing of Atlantic bluefin tuna is a big problem and the fishery has been plagued by lack of enforcement and control.

What WWF Is Doing

WWF focuses on transforming the global tuna fisheries market and improving the way tuna fisheries are managed and governed. Our approach is for tuna stocks to be managed as integral parts of the entire marine ecosystem. WWF works on seven tuna populations with the highest market value and therefore most vulnerable to overfishing: the Atlantic, Southern and Pacific bluefin, bigeye, yellowfin, albacore and skipjack tuna. We work with other organizations as well as the fishing, processing and retailing sector to transform tuna fishing into a sustainable business. Our goal is to achieve Marine Stewardship Council (MSC) certification for healthy and well-managed tuna populations.

Stopping Overfishing

In the Mediterranean, WWF has been working for over 10 years to protect Atlantic bluefin tuna. We work to stop overfishing and ensure recovery of the Eastern Atlantic and Mediterranean stock. WWF has been very influential in most of the decisions made by the International Commission for the Conservation of Atlantic Tunas (ICCAT), the body that regulates the fisheries.

Tuna Tagging

Since 2008, WWF has been tagging Atlantic bluefin tuna in the Mediterranean Sea to learn more about the species. The data collected so far has helped us learn more about their migratory behaviors and enabled us to advise fisheries managers on how best to protect the species. With more field tagging work, WWF and its partners can continue to fill the gaps on the bluefin’s biology and help give this emblematic fish a chance at survival for the long term.